[Midnightbsd-cvs] src: sx.h: Add a new macro, sx_xlocked(), that returns true if the

[laffer1 at midnightbsd.org]

Log Message:
-----------
Add a new macro, sx_xlocked(), that returns true if the current thread holds an exclusive lock on the specified sx lock.

Tags:
----
RELENG_0_1

Modified Files:
--------------
    src/sys/sys:
        sx.h (r1.1.1.1 -> r1.1.1.1.2.1)

-------------- next part --------------
Index: sx.h
===================================================================
RCS file: /home/cvs/src/sys/sys/sx.h,v
retrieving revision 1.1.1.1
retrieving revision 1.1.1.1.2.1
diff -L sys/sys/sx.h -L sys/sys/sx.h -u -r1.1.1.1 -r1.1.1.1.2.1
--- sys/sys/sx.h
+++ sys/sys/sx.h
@@ -76,6 +76,7 @@
 	SYSUNINIT(name##_sx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    sx_destroy, (sxa))
 
+#define	sx_xlocked(sx)		((sx)->sx_cnt < 0 && (sx)->sx_xholder == curthread)
 #define	sx_slock(sx)		_sx_slock((sx), LOCK_FILE, LOCK_LINE)
 #define	sx_xlock(sx)		_sx_xlock((sx), LOCK_FILE, LOCK_LINE)
 #define	sx_try_slock(sx)	_sx_try_slock((sx), LOCK_FILE, LOCK_LINE)
@@ -84,13 +85,12 @@
 #define	sx_xunlock(sx)		_sx_xunlock((sx), LOCK_FILE, LOCK_LINE)
 #define	sx_try_upgrade(sx)	_sx_try_upgrade((sx), LOCK_FILE, LOCK_LINE)
 #define	sx_downgrade(sx)	_sx_downgrade((sx), LOCK_FILE, LOCK_LINE)
-#define	sx_unlock(sx)	\
-		do { \
-			if ((sx)->sx_cnt < 0) \
-				sx_xunlock(sx); \
-			else \
-				sx_sunlock(sx); \
-		} while (0)
+#define	sx_unlock(sx) do {						\
+	if (sx_xlocked(sx))						\
+		sx_xunlock(sx);						\
+	else								\
+		sx_sunlock(sx);						\
+} while (0)
 
 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
 #define	SX_LOCKED		LA_LOCKED